NISARPUR, INDIA
— When Arundhati Roy arrives late at night in this little river hamlet, she is mobbed and pelted with flowers. They love her here. And why not? She wants to help save their town.

Ms. Roy arrived as a public figure on the larger Indian scene only two years ago, like some dramatic, unforeseen comet. When sales of her highly original first novel, "The God of Small Things," went through the roof worldwide, it put Indian writing firmly on the map and gave this country something it never had - a bona fide celebrity author. John Updike compared Roy's arrival in fiction to that of Tiger Woods in golf.

Yet Roy is more than an exotic literary figure in her native land. She has emerged as a kind of populist conscience, a budding Pablo Neruda of India, an upstart who has bravely taken on some of India's most sacred cows.

Last year, as the nation celebrated its nuclear tests, Roy wrote a blistering critique, describing them as "folly." She made headlines by donating time and money to untouchable, or "Dalit," writers. Recently, she helped inspire and organize a massive week-long protest against one of the dams on the Narmada River that may submerge 245 villages.

In so doing, Roy shed her role as one of India's favorite daughters and became one of its most controversial - though few disagree that, right or wrong, she's had a terrific impact on debates that lie at the heart of a country whose population this week reached 1 billion people. Like many artists she worries about the rise of extremism and a more aggressive Hinduism. But her main concern is the ever-rising gap between modern urban India and the vast poverty found in the villages.

Indeed, Roy's identification with villagers, and their admiration of her, is unusual. Famous artists here mostly inhabit a stratified world of heady seminars and splendid isolation. Not many are folk heroes willing to deal with bedbugs and bumpy roads as Roy has done in the past few weeks on the rally.

Yet Roy's outsider status is one reason her voice has emerged, say those close to her. "She is not an academic. The people she knew and grew up with were underdogs," says Rana Behl, a friend and historian at Delhi University. "She did not come through the normal patterns of social politeness and the caution public figures here are used to. She's not cut as an elite Anglo-Indian writer."

Roy's strength, say friends, is a passionate sense of justice and a feeling for everyday problems - one reason her writing attracts PhD candidates and ordinary people alike. Her appeals in print, whether for an end to the South Asian arms race, or for equal treatment of villagers, has a 19th century abolitionist fire: "Prevalent political wisdom suggest that to prevent the State from crumbling, we need a national cause, and other than our currency (and poverty, illiteracy) we have none. This is the road that led us to the bomb," she wrote in an essay that itself hit India's intelligentsia last year like a bomb.

"The young lady's writing on the Narmada dam has forced the question of the treatment of village people into urban drawing rooms where it might not have been raised," argues Sumer Lal, a senior editor at The Hindustan Times, Delhi's largest circulation newspaper. "She has married passion and facts and breathed life into a social movement that had given up hope."

Not everyone is so complimentary. This spring, after the Supreme Court of India lifted a stay on construction of the Sardar Sarovar dam on the Narmada, Roy published a highly critical essay, "The Greater Common Good." The tract so upset the Supreme Court that in July several justices said Roy had "undermined the dignity of the court," and sought action against her. In the state of Gujarat, supporters of the dam burned the book in public. An increasingly hostile Indian press often now sneers at Roy as impractical or naive. One paper called her "The Goddess of Large Causes."

Still, the photogenic Roy, who has been on several lists of "the 50 most beautiful women in the world," has made herself hard to ignore. "Some people say I am using my fame," Roy says. "I say I am letting my fame use me. The space for disagreement, not only in this country, but also abroad, is shrinking. Critics say we are urban elites and so can't comment on rural problems, as if being urban is a crime. What they really want is that only powerless people in the village should protest, because they know such people can easily be crushed underfoot.

"People say I'm too passionate. Well if you can't get passionate about 40 million people displaced [the estimate of how many lost homes around the hundreds of dams in the Narmada valley] and losing their jobs, what can you get passionate about?"

In some ways her Cinderella story still surprises Roy.

After a stint living on the beach as a fruit-juice seller, Roy left her husband, returned to Delhi without a place to stay, and was so poor she hocked a ring for 300 rupees ($7) and a banana shake. In 1996, after working as an aerobics instructor, and then as a screenwriter, the bank closed her account.

During this time, however, she started work on the manuscript that became "The God of Small Things," writing for herself in a regimen from 9 a.m. to 3 p.m. every day for five years.

Mostly, she plumbed her past, growing up as the daughter of a Syrian Christian in the lush tropical state of Kerala on South India's west coast. It is a partly tragic story told through the innocent but shrewd eyes of a young girl, a twin, and culminates in a "forbidden" theme, a love affair between an upper-caste woman and a Dalit.

When Roy showed the manuscript to an editor from Harper-Collins in Delhi, Pankaj Mishra, Indian writing was being "discovered" in the West. Mr. Mishra was so excited by the unusual syntax and rhythm of the novel that he told Roy she had written a blockbuster. She got a $1 million advance, and fueled a frenzy over Indian writing that has yet to end.

By unanimous vote, the novel won Britain's Booker Prize. In India the Booker is treated as the Pulitzer and Nobel prizes put together. Salmon Rushdie was the last Indian to win, in 1982, for "Midnight's Children," itself a seminal novel. (Unlike Roy, Mr. Rushdie, who lives in London, is not embraced here). The prize gave Roy star status.

Questioning the status quo

Yet she has always challenged norms, always been a questioner. "From a very early age I was determined to negotiate with the world on my own," she says. As an architecture student she argued that the final contest thesis should be written, not drawn. Her written thesis won. One local physicist first noticed Roy during a debate in the mid-'90s over "Bandit Queen," a film about a real-life tribal woman who is raped and later becomes a renegade heroine. Censors wanted to cut some nude scenes. The artistic left portrayed critics of the film as cultural troglodytes opposed to free expression. But Roy took another view.

"She stood up to the left and said, 'Hey, this is just another rape and retribution film. It still exploits women,' " remembers the physicist, Lekha Nair. "It was pretty brave, actually."

In person, at 7 a.m., Roy emits a whiff of the bohemian, a whiff of the '60s, a whiff of Marin County, Calif. - and a rapier-like intelligence. She also seems unimpressed with herself.

"I find that in our society today it has become much easier to ignore the little ugly things, the things we never would have before.

"When you come to a place like the Narmada Valley, you understand that these village people are not understood in Delhi. It has become easier to hate, or ignore them. Who wants to pay attention? You don't notice unless something is on TV, and if it isn't there, it doesn't exist."

At one point Roy delightedly points out a mongoose running along a roofline, and turns it into a metaphor for her own new battles: "That's perfect! I identify with Rikki Tikki [a cobra-fighting mongoose made famous by Rudyard Kipling]. I tell my friends, I am like Rikki Tikki. I just need to hold on. I may get thrashed around by the cobra. But I will still hold on."